1. Field of the Invention
The present invention relates to a method of and an apparatus for guiding a moving object such as an unattended transporting vehicle and the like used in a factory for factory automation (FA), particularly, it relates to a guiding method and apparatus using a presumption navigation.
2. Description of the Prior Art
As methods of guiding a moving object such as an unattended transporting vehicle and the like, the following methods may be given, that is, a method of presetting a continuous traveling path by means of guide cables, optical tapes, etc. so as to move a car along the path, a method of incorporating the recognition function of the traveling path in the moving object itself, thereby peripheral environments of the traveling path are recognized by means of electric wave or light so as to move the car according to the information, and a method of applying the presumption navigation to guide the car.
The method of setting the traveling path by means of the guide cables costs much money and time for setting the path and can not be changed simply, and when using the optical tapes, the detecting accuracy of traveling path is deteriorated by stains on the tape surface due to accumulative uses. Also, in the method of recognizing the peripheral environments by the electric wave or light which is susceptible to external faults, the detecting accuracy is deteriorated.
As a method without such disadvantages, the method of applying the presumption navigation to input information of the traveling path to the moving object itself so as to be guided by the information is proposed in Japanese Patent Application Laid-Open No. 20508/1988 by the inventor of the present invention and others.
In this guiding method, a self-control vehicle starts from arbitrary position and detects the number of revolutions of right and left wheels at constant intervals respectively, then estimates its position and direction on the basis of the factor determined by the number of revolutions and wheel specification, sets a target position based on the estimated position and direction and travels along the preset traveling path as traveling to the target position, at each detection of marks arranged on suitable positions on the traveling path, corrects its position and direction as well as detects the deviation thereof at correction, changes the factor related to the deviation depending upon whether the deviation detected is of the position or direction, and travels as applying the changed factor as the new factor. Thereby, the guiding accuracy is improved and the self-control vehicle is no longer guided to the position far away from the marks.
In the conventional guiding method employing the presumption navigation, however, such a difficulty was encountered that, since the traveling path can be set only linearly and its freedom of setting is restricted, when the shunting operation is required for plural cars traveling on the same traveling path opposedly, the car can not be guided smoothly and the shortest path can not be selected, so that in the case where the moving time is restricted, it can not be shortened responding thereto.